Friction chain drive

ABSTRACT

The device consists of an endless link chain drive rotatable by a conventional sprocket driven by a suitable motor. The chain element is intended to encircle and to drive a rotary object such as a wheel or drum (e.g. the drum of a concrete mixer). A circumferential band or belt of resilient material is applied to the periphery of the wheel or drum with which the chain makes frictional contact. The resilient belt is applied by a suitable material of adhesive nature to the wheel or drum to be driven. A tensioning device such as a tension bolt to adjust the spacing between the sprocket and drum, allows adjustment of the amount of frictional contact of the chain with respect to the belt. Spaced metallic feet carried by the chain may be employed to make contact with the belt. The above arrangement allows for a desirable and adjustable amount of slippage between the driving and driven elements to prevent damage to the elements and their connections.

United States Patent Inventors John T. Craft Sturgis, S. Dak.; John D.Forbes, Overland Park, Kans.; Merle E. Vig, Mud Butte, S. Dali. Appl.No. 7,588 Filed Feb. 2, 1970 Patented Aug. 17, 1971 Assignee JolynCorporation Sturgis, S. Dak.

FRICTION CHAIN DRIVE 5 Claims, 3 Drawing Figs.

US. Cl 74/219, 74/203, 74/242. 15 R Int. Cl Flfih 7/00,

Fl6h 15/00, F16h 7/10 Field of Search 74/219, 221, 229, 242.15 B, 203,207

References Cited UNITED STATES PATENTS 3,406,582 10/1968 FrentzelABSTRACT: The device consists of an endless link chain drive rotatableby a conventional sprocket driven by a suitable motor. The chain elementis intended to encircle and to drive a rotary object such as a wheel ordrum (cg. the drum of a concrete mixer). A circumferential band or beltof resilient material is applied to the periphery of the wheel or drumwith which the chain makes frictional contact. The resilient belt isapplied by a suitable material of adhesive nature to the wheel or drumto be driven. A tensioning device such as a tension bolt to adjust thespacing between the sprocket and drum, allows adjustment of the amountof frictional contact of the chain with respect to the belt. Spacedmetallic feet carried by the chain may be employed to make contact withthe belt.

The above arrangement allows for a desirable and adjustable amount ofslippage between the driving and driven elements to prevent damage tothe elements and their connections.

PATENIEnAummn 3599502 FIG.I

F 2 INVENTOIB JOHN T. CRAFT JOHN D. FORBES MERLE E.V|G

BY ,g/m

ATTORNEYS FRICTION CHAIN DRIVE BACKGROUND OF THE INVENTION The device isbroadly a transmission mechanism for driving a rotary device from apowered rotary source, wherein provision is made to protect the devicefrom damage due to variations in the rotational speed of thetransmission.

BRIEF SUMMARY OF THE INVENTION Very few transmissions of the typebroadly described above are driven at a constant rate, either due to therequirements, or for accidental reasons. When a given driven gear,sprocket, belted wheel or the like, is suddenly slowed, stopped, or evenreversed, damage can obviously occur, and many various means have beendevised to avoid such damage.

Frictional transmissions are known, usually consisting of a poweredresilient wheel making frictional contact with a similar driven wheel.Such transmissions have low load capacity, and suffer wear when slippageoccurs. An example of this type of transmission can be seen in thepatent to Merle E. Vig, U.S. Pat. No. 3,369,799, granted Feb. 20, I969for a Tractor Mounted Concrete Mixer, wherein a motor 31 drives afriction wheel 32 pressed into contact with a friction belt applied tothe periphery of a concrete mixer drum for rotating the latter. Thepresent invention has highly practical advantages for use in thisparticular machine, hence the appended drawings will slow similaritiesto the patent drawings, for simplicity of the illustration. The varioususes of the present invention are not, of course, limited to this typeof concrete mixer or to concrete mixers in general.

The present invention has among its advantages the elimination of amechanical driven gear, sprocket, or the like. Instead is provided onthe driven element a nonmetallic resilient band of durable material(such as cord reenforced rubber) over which a link-type, chain driven bya sprocket engages the resilient band which is affixed to the wheel,drum, barrel or the likethe element to be driven.

When the driven element (further referred to as a drum) is (a)imperfectly shafted, or (b) is out of round at the connection point withthe chain, or (c) subjected to abrupt changes in driven speed, or (d)subjected to hard usage under use over hard terrain or exposure to dirtor weather, breakdowns and damage can obviously occur.

According to the present invention, a power-operated sprocket mounts alink-type driving chain which is spacedly entrained over a rotatabledrum, with the interposition of a broad belt or band of resilientmaterial bonded to the drum by a suitable adhesive so' as to underliethe chain. The sprocket, and hence the chain, are rendered adjustablewith respect to the drum so as to control the tension of the chain uponthe belt, to conform to load factors.

The flexible link driving chain may be equipped with spaced feet toincrease engagement with the flexible or resilient belt and these feetmay be further equipped with pins or rivets for partial penetration intothe belt. Under heavy load conditions other rivets or like connectorsare employed to supplement the adhesion of the belt to the drum.

The above elements may obviously be duplicated to suit varioustransmissions or load factors.

B EFDES Q F THED A N S plication of a single chain link bearing one ofthe feet which engage the resilient belt shown in FIGS. 1 and 2.

DE L- D DESC PTION or. T E DRAWING A housing lfl attached to a machinesuch as a concrete mixer is supported as by tubular supports llil, thesebeing shown broken away. Housing 16 contains a motor 12, preferably afluid-type motor remotely controlled and powered. Motor 12 is carried bya bracket 15 pivoted to housing 10 as by a bolt 16. The opposite side ofthe bracket I5 carries an extension 17 bored to receive the end of atension bolt 20 whose upper end passes externally of housing 10 througha suitable bore.

Shaft 21 of motor I2 carries a sprocket 22 over which is trained anendless link chain 23. Numeral 25 represents a portion of the element tobe driven, like part of the drum of a concrete mixer. The means forrotationally supporting drum 25 is not shown but may be the same asshown in the abovementioned U.S. Pat. No. 3,369,799.

Secured around the outer periphery of drum 25 is a heavy duty belt ofresiliently formed material 26 such as reinforced rubber or rubbersubstitute. Belt 26 is centered around drum 25 in such position thatthat it will underlie and rotate on the same axis as chain 23. Belt 26is secured to drum 25 by a suitable adhesive. Additionally reinforcingconnectors such as rivets 27 may be used to assist the adherence of belt26 to drum 25, and are specially employed where belt 26 is not of theendless variety. In this case rivets 27 are used adjacent the locationwhere the ends of belt 26 abut.

The ability of chain 23 to make frictional contact with belt 26 isenhanced by including in chain 23 spaced links 30 of the type shown inFIG. 3. The sidewalls of links 30 are formed with angled extensions orfeet 311 to further assist traction of chain 23 upon belt 26. Feet 31carry pins such as rivets 32 which partially penetrate belt 26, whenextra traction is needed.

MODE OF OPERATION By the adjustment applied to tension bolt 20, thespacing between sprocket 22 and drum 25 can be varied which results in aselective degree of tension applied to chain 23 and hence exerted uponthe resilient belt 26. More such tension is obviously needed where thedrum 25 carries a heavy load to be rotated.

When the transmission is in normal operation, the tension applied tochain 23 is not too great to prevent a certain amount of flexibilitybetween driving and driven elements.

The resilient belt 26, however, greatly enhances this flexibility, withthe result that sudden changes in the driving speed, stopping suddenly,reversal, or the like are absorbed by the flexibility of the partsdescribed which eliminates or substantially reduces damage.

What we claim is:

l. A transmission including a housing containing a motor, a sprocketshafted to said motor, a rotationally mounted driven member spaced apartfrom said sprocket, a chain drive trained over said sprocket and aroundsaid driven member, said driven member having circumferential resilientmeans bonded externally thereto in operational contact with said chaindrive, and means adjusting the tension of the chain drive for varyingthe amount of frictional contact applied by said chain drive to saidresilient means.

2. The transmission according to claim I, wherein the means foradjusting the tension of the chain drive comprise means for varying thespacing between the sprocket and the driven member.

3. The transmission according to claim 2, wherein the means foradjusting the tension of the chain drive includes a pivoted mountingbetween said motor and its housing, and means on said housing forshifting said motor toward or away from said driven member.

4. The transmission according to claim I, wherein selected links of saidchain drive are equipped with extensions flatly engaging said resilientmeans to increase increase traction therewith.

5. The transmission according to claim II, where selected a links ofsaid chain drive are equipped with pins positioned to penetrate saidresilient means.

1. A transmission including a housing containing a motor, a sprocketshafted to said motor, a rotationally mounted driven member sPaced apartfrom said sprocket, a chain drive trained over said sprocket and aroundsaid driven member, said driven member having circumferential resilientmeans bonded externally thereto in operational contact with said chaindrive, and means adjusting the tension of the chain drive for varyingthe amount of frictional contact applied by said chain drive to saidresilient means.
 2. The transmission according to claim 1, wherein themeans for adjusting the tension of the chain drive comprise means forvarying the spacing between the sprocket and the driven member.
 3. Thetransmission according to claim 2, wherein the means for adjusting thetension of the chain drive includes a pivoted mounting between saidmotor and its housing, and means on said housing for shifting said motortoward or away from said driven member.
 4. The transmission according toclaim 1, wherein selected links of said chain drive are equipped withextensions flatly engaging said resilient means to increase increasetraction therewith.
 5. The transmission according to claim 1, whereselected links of said chain drive are equipped with pins positioned topenetrate said resilient means.